DB2 for z/OS: Data Sharing in a Nutshell

126 Data Sharing in a Nutshell

If false contention exceeds 1%, we would recommend increasing the LTEs to the

next power of 2.

REQ DEFFERED shows how many lock requests were deferred, usually

because of contention. The -CONT field of 842K identifies all contention, whether

it is for:

򐂰 FC contention, where two different objects hash to the same LTE

򐂰 XES contention, where the same table is open with an S mode Logical lock

(L-lock)

򐂰 IRLM contention, where two different members want an exclusive lock on the

same page

From RMF you can identify only global contention (REQ DEFERRED) and

FALSE CONT. For IRLM and XES contention you need to look at the

SUSPENDS - XES GLOBAL CONT and SUSPENDS - IRLM GLOBAL CONT

fields in the OMEGAMON XE for DB2 PM/PE Statistics ...